Thread: Choosing a converter

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Welcome to CHR

Rear end ratio has a lot to do with stall speed as well. In that vintage (1979-1981), automatic transmission equipped Trans Ams and Z-28s came from the factory with 2.41, 2.56, or 2.73 rear end ratios depending on engine/transmission combinations. I believe there was an optional 3.23 positraction with the 400 HO package. Four speeds were typically 3.08.

Not knowing what your rear end ration is or how long your cam duration is it would be difficult to come up with "exact" numbers for the stall speed. In that the car weighs 3550 pounds and the 455 will add a few more I would agree with Don’s advice to go somewhere between 2400-2600. If you have the 3:23 posi, go 2400 – if you have 2:73 or 2:56 go with the higher stall speed.

Give us some more information, i.e., how you’re intending to drive the car, engine modifications, and rear end ratio for a more “precise” answer. While I also agree that high tech is filtering down to hot rodding, converter selection is not a science, rather a combination of “what-ya-got and how-ya-want-to-launch”

Regards,
Glenn

Big thing to remember is the smaller the converter, the more heat the trans will make. Having a good tranny cooler is key to any transmission and NOT the one connected to the radiator.